The invention deals with moulding installations for box moulding, in which in each case one part of the mould is moulded in a lower and in an upper box and generally this takes place by compacting moulding sand using a corresponding pattern. The upper box and lower box are separately moulded and, generally after inserting cores in the lower boxes, folded together for the formation of the mould.
High capacity moulding installation (more than 120 moulds per hour) have two moulding machines. In one machine the upper box mould is produced, while the lower box mould is produced in the lower box mould. However, with the known moulding installations it is either not possible or is only possible with considerable constructional expenditure in connection with the conveying means to utilize the fundamentally possible high hourly outputs of modern moulding machines.
Known moulding installations of the aforementioned construction have two conveyors with, the moulding machines for the upper and lower boxes being arranged in spaced succession on one of the two conveyors in the conveying direction. The empty moulding box comprising the upper box and the lower box is supplied to a transfer apparatus on a first conveyor, which is normally constructed as a pallet conveyor or other construction conveyor. The transfer apparatus has two successively arranged box locations and bridges the distance to the second conveyor, which is passed through by the two moulding machines. The transfer apparatus is constructed as a double apparatus and takes over the upper box and at a lower level the lower box and moves the two box parts simultaneously to two empty locations on the second conveyor. While the empty pallets are moved on the first conveyor belt to a second transfer apparatus, the lower and upper boxes are successively supplied on the second conveyor by a sliding or thrust drive to the successive moulding machines. As on the second conveyor the upper and lower boxes constantly change and simultaneously an upper box must be moved into one moulding machine and a lower box into the other, and the feed drive on the second conveyor during each working cycle must cover a conveying path which is twice the size of a box in the conveying direction. This conveying path can be more than three meters when there is a large box spacing. The feed drive generally constituted by a hydraulic cylinder therefore has a correspondingly complicated construction. It is also necessary to control high accelerating and decelerating forces. However, for the first conveyor a much more simple sliding drive can be chosen, because it only has to cover half the conveying path.
The lower box is moulded on the first moulding machine in the conveying direction and the upper box on the second machine. The upper and lower boxes then pass into a second transfer apparatus, which returns the moulded upper box to the first conveyor, whereas the moulded lower box passes on the second conveyor into the following core inserting line. Parallel to the core inserting line the moulded upper boxes are moved on the first conveyor. As a result of this conveying principle the working cycle behind the second transfer apparatus must be again shortened to half the conveying path. This initially presupposes a braking mechanism acting against the sliding drive and a further drive in the core inserting line, while a further braking mechanism must be provided at the end of the core inserting line. It is finally pointed out that, on the first conveyor behind the second transfer apparatus there is also a funnel-shaped auger for producing holes for the pouring gate, riser, ventilating openings, etc. in the upper box mould.
In the known moulding installation the available running time is shortened by approximately half the time necessary for the conveying path for the two box parts on the second conveyor. Not only are the drives for the boxes in the second conveyor complicated and fault-prone, but also the two transfer apparatuses are different and, in particular, the first transfer apparatus for the upper and lower boxes has a very complicated construction. Finally, on the second conveyor between the two transfer apparatuses the pallets run empty, so that unnecessary motive energy is consumed in the first conveyor.